Method of treating potash-bearing silicates.



W. GLAESER.

METHOD OF TREATING POTASH BEARING SILICATESB APPLICATIDN FILED MM. 9. 1911.

1,254,677. Patented Jan. 29, 1918.

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WALTER GLAESER, OF BROOKLYN, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO POTASH EXTRACTION CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OI TREATING POTASH-BEABING SILICATES.

To all whom it may concern:

Be it known that I, WALTER GLAESER, a subject of the German Emperor, and a resident of Brooklyn, county of Kings, and State of New York, have invented a new and useful Improvement in Methods of Treating Potash-Bearing Silicates, of which the following is a specification, the rinciple of the invention being herein exp ained and the best mode in which I have contemplated applying that priociple, so as to distinguish it from other inventions.

The present improvements relate to a method of treating )otash-bearing silicates, such as feldspar and analogous minerals for the purpose of rendering the potash content of the same available for use in agriculture as a fertilizer. It is well known that such silicates are abundant in this country, but the potash content of the silicates which is very valuable for agricultural purposes, is not in such form that the feldspar can be used as a fertilizer, the potash content being almost completely insoluble in water. The present invention has for its object the treatment of the silicates in a simple and inexpensive manner to render this potash content water soluble, and to thus render available for agricultural purposes the vast deposits of such material which are to be found racticall all over the eastern part of the Ilnited tates as well as in many other places. To the accomplishment of t e foregoing and related ends, said invention, then, consists of the means and method hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain means and one mode of carryin out the invention, such disclosed means an mode illustrating, however, but one of various ways in which the principle of the invention may be used.

In said annexed drawings Figure 1 is a central vertical section through one form of apparatus which can be utilized in carrying out my improved method; and Fi 2 is a central vertical section taken at right angles to the plane of Fig. 1 through the container for the .material.

The method can best be described with reference to the apparatus shown in the draw- Speciflcation of Letters Patent.

Patented Jan. 29, 1918.

Application filed March 9, 1917. Serial 1705153324.

ings, although it will be understood that other forms of apparatus may be employed if desired, the present construction being but one of a number of forms and being adapted primarily for treatin small amounts of the material. In Fig. 1 there is shown a furnace Chamber 1 having the grate 2 in an extension at one side and permittin the products of combustion to pass latera lly from this extension around a cylinder 3 adapted to contain the material, after which the heated gases pass through a stack 4. The chamber 5 in which is received the container 3, is of substantially rectangular form, and is constructed to give an equal distribution of the gases on all sides of the container.

The container comprises an iron or steel casing 7 lined internally with suitable refractory materials such as fire brick 6 and rotatably mounted concentrically within a suitable protective easing 8, also of refractory material. In this we the gases are prevented from coming in irect contact with the container and no products of combustion pass over, or come in contact with, the material received within the container, although the temperature of this container is substantially the same as, or higher than,

that in the chamber 5.

The casing 7 is rotatably mounted, as stated, bein held in the walls of the furnace at one end in a roller bearing 9 and at the other end in a lain bearing 10, which of course are sufliclently loose to permit of the expansion of the iron shell 7 under the high temperature which is to be maintained in the furnace, Attached to a fixed end wall 11 of the casing is a shaft 12 driven by a motor 13 so that the casing may be rotated. At its other end the casing is closed b means of a removable cap 14 aperture at its center to permit of the passage therethrough of a conduit 15 which is attached to a movable end or iston 16 fitting snugly withinthe casing and normally maintained in alinement with the wall 17 of the furnace, so that the effective length of the cylinder is the same as the length of the furnace. The end of the conduit 15 is partially closed by a cap 18, provided, however, with an open nozzle 19, which permits of the escape of the gases evolved during the heatin It will be understood t at the apparatus as here shown exemplifies merely one form of the mechanism which may be used in connection with the process to be presently described. Furthermore, the apparatus here shown is intended for use with small amounts of material only and if larger amounts are used the apparatus will necessarily be changed to secure greater speed and facilities for handling the material.

The silicate, and I will refer particularly to feldspar for an illustration, is first prepared by being crushed to a convenient slze and heated to between 800 and 900 C. in an open kiln. After this heating has continued for several hours, the material is removed and suddenly chilled, and is thus rendered amorphous and easily broken up, and is then ground to preferably the fineness of an 80 mesh screen or even finer. This preliminary treatment of the felds ar is not new and has been before employed y those attempting to treat feldspar for the purpose of rendering the potash content water soluble.

The powdered amorphous feldspar is then mixed with calcium chlorid preferably in equal parts, and to this mixture about 5 per cent. of iron, or an oxid of iron, or of iron containin coke, or of mixture of coke and iron or o powdered pyritis, or pyritis clinker, is added. The resulting mixture is then dried thoroughly, preferably at a temperature around 500 F. in a rotary drier,-

and the heating of the material is continued until the moisture has been driven off, since it has been found that unless the material is thoroughly dried the subsequent extraction of potash in water-soluble form is retarded and the yield is only to 80 per cent. of the content. If the material has een thoroughly dried the yield can be maintained at between 95 and 100 or cent. of the total potash content of the feldspar. The resultant mixture is then charged into the container 6 in powdered or finely granular condition, the movable end or the piston 16 is moved into alinement with the end wall 16 of the furnace and the casin is then rotated while the temperature is raised to about 1000 C. and maintained for about one or two hours. The bestresults have been obtained at a temperature of about 1000 0., although the process is workable at slightly lower temperatures. It is desirable, however, to maintain the tem erature at 900 or above. The length of time and the temperature depend to some extent upon the particular material to be treated, and some materials, such for example as lepidolite, leucite and others, require only about one-half hours treatment at a temperature of about 800 C.

During this heating action a certain amount of gas is evolved and this gas is rmitted to escape from the open nozzle 19 of the conduit 15. The products of commaterial either b bustion are admitted to the container since a reducing or non-oxidizing atmosphere must be maintained therein. Calcium chlorid, while the most desirable material for this purpose from some standpoints, is not the only substance suitable as I have employed sodium chlorid in this step of the process with very good results.

The action that takes place in the material during this heating is indicated by the followin reaction equations which show that the iron or coke or the mixture of both, depending upon which is used, acts as a contact substance to transform the calcium chlorid into ferric chlorid and calcium oxid after which the ferric chlorid attacks the feldspar producing ferric oxid, calcium aluminum silicate and potassium chlorid. If coke alone is used with the material it operates as a contact substance by reason of the fact that all coke contains a small amount of iron oxid, and iron in any amount is of course a contact substance for the present reaction. In addition to the small amount of iron which is usually contained in coke, and which is around five per cent, there is a slight amount of iron which comes from the walls of the pipe or conduit through which the material passes, through abrasion, and this iron is added to that contained in the coke and also serves as a contact substance.

The reaction that takes place when calcium chlorid, and iron oxid are used is represented by the equations:

When magnetic iron oxid is used the reactlon is represented Feel, BKCl Fe,,(), 4(CaO.

If metallic iron is used the reaction is as follows:

CaCh-i-Fe-i-O CaO+FeCl K,O.Al,O,.6SiO +CaO-l-FeCl,=

KCl-l-FeO--i-CaOAl,O,.6SiO If coke is used, the reaction may be represented:

It will be understood that in the precedin reaction equation the iron oxid or meta lic iron that may be contained in the reason of abrasion of the iron conduit m which the material is usually treated or by reason of the iron oxid that is usually found in. coke, is not considered, as the action of the iron or iron oxid on the material has previously been given in other equations.

The free oxygen indicated in the equations where metallic iron is used and where coke is used, is that small amount of oxygen that will leak into the apparatus no matter What precautions are taken to prevent its introduction and it will be understood that the amount is in any case small. It is possible to secure the desired action on the feldspar Without the aid of any contact substance although such a substance will preferably be employed. If no contact substance is used, the reaction is represented as follows From the foregoing equations the reactions that take place when sodium chlorid is used with feldspar and coke, iron or iron oxid will be readily understood as they are similar to the ones 'ven above. This reaction continues until the ferric oxid (or other contact substance or catalytic agent) which is always regained, has reacted upon all of the calcium chlorid to produce enough ferric chlorid to react with the total potash content of the feldspar. After several hours heating, which is sufficient to cause the reaction to go to completion, the temperature is permitted to drop and the cap 14 from the casing 6 is then removed, permitting the conduit 15 and the end 16 to be also removed when an operator can rake the material in the container into that portion of the latter which is outside of the furnace and it is therefore comparatively cool. In other types of apparatus the temperature may not be permitted to drop at the end of the several hours heating, but it may be maintained at the same temperature while the material is being removed and this will be the preferable procedure in continuously operating plants. After the material has been thus moved to a cool part of the container the cap 14 and end 16 are replaced as the material must not cool in contact with the atmosphere or the resultant materials will react and potash in a water soluble condition is not secured as a part of the product.

The mixture then contains potassium chlorid, calcium aluminum silicate and compounds of iron with oxygen or chlorin, and

if desired this entire mixture can be used as a fertilizer, although preferably the potassium chlorid will be se arated from the 'mass and used alone, but 0 course this process of separation forms no part of the present invention and various methods may be employed for isolating the potassium chlospar, and the process is not an expensive one, since no expensive reagents are required, and the length of time necessary to complete the reaction is not over two hours, and is generally about an hour and a half.

The mixture when ready for the final heating must be free from water in any form, and if water is present the calcium chlorid is reduced to calcium oxid and hydrochloric acid, which of course interferes with the reaction desired, since the re-agent, CaCh, is partially destroyed.

()ther modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the process herein disclosed, provided the step or steps stated by any one of the following claims or the equivalent of such stated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a method of treating potash bearing silicates, the steps which consist in drying a mixture of finely divided silicate, and a water soluble metal chlorid, and then heating the same out of contact with the atmosphere at a temperature above 900 C.

2. In a method of treating potash bearing silicates, the steps which consist in drying a mixture of finely divided silicate, and a water soluble metal chlorid, and then heating the same out of contact with the atmosphere with av reducing contact substance at a temperature above 900 degrees C.

3. In a method of treating potash bearing silicates, the steps which consist in drying a mixture of finely divided silicate, and a water soluble metal chlorid, and then heating the same in a non-oxidizing atmosphere at a temperature above 900 degrees C.

4. In a method of treating potash bearing silicates, the step which consists in furnacing a dried mixture of finely divided silicate and a water-soluble metal chlorid in a nonoxidizing atmosphere at a temperature above 900 degrees C. v

5. In a method of treating potash bearing silicates, the steps which consist in drying a mixture of finel divided silicate, and a Water soluble meta chlorid at a temperature of about 500 F., and then heating the same with a reducing contact substance at a temperature above 900 degrees C.

6. In a method of treating potash bearing silicates, the steps which consist in drying a mixture of finely divided silicate, and a water soluble metal chlorid at a temperature of about 500 F., and then heating the same with a reducing contact substance in a nonoxidizing atmosphere at a temperature above 900 C.

7. In a method of treating potash bearing silicates, the ste s which consist in thoroughly mixing nely divided silicate with about an equal amount of water soluble metal chlorid and about five per cent. of a reducing contact substance, and drying such mixture, and then heating the same in a nonoxidizing atmosphere at a temperature above 900 degrees C.

8. In a method of treating potash bearing silicates, the steps which consist in thoroughly mixing finely divided silicate with about an equal amount of water soluble metal chlorid and about five per cent. of a reducing contact substance, drying such mixture at a temperature of about 500 F. and then heating the same in non-oxidizing atmos-' phere at a temperature of about 900 C.

9. In a method of treating potash bearing silicates, the steps which consist in thoroughly mixing finely divided silicate with about an equal amount of a water soluble metal chlorid and about five per cent. of a reducing oxid of iron, drying such mixture, and then heating the same in a non-oxidizing atmosphere at a temperature of above 900 C.

10. In a method of treating potash bearing silicates, the steps which consist in thoroughly mixing finely divided ,rsilicate with about an equal amount of calcium chlorid and about five per cent. of a reducing oxid of iron, drying such mixture, and then heating the same in a non-oxidizing atmosphere at a temperature of above 900 C.

11. In a method of treating potash bearing silicates, the steps which consist in thoroughly mixing finely divided silicate with about an equal amount of a water soluble metal chlorid and about five per cent. of a reducing contact substance, drying such mixoughly mixing finely divided silicate with about an equal amount of a water soluble metal chlorid and about five per cent. of a reducing contact substance, drying such mixture, heating the same in a non-oxidizing atmosphere at a temperature of above 900 0., and then cooling such mixture in a nonoxidizing atmosphere.

13. In a method of treating potash bearing silicates, the steps which consist in heating a mixture of anhydrous silicate and anhydrous calcium chlorid in a non-oxidizing atmosphere at a temperature of 800900 C.

14. In a method of treating potash bearing silicates, the steps which consist in heating a mixture of anhydrous silicate and anhydrous calcium chlorid .in a non-oxidizing atmosphere and in the absence of water vapor at 800900 C.

Signed by me, this 21st day of February,

WALTER GLAESER. 

